Numerous attempts have been made to inactivate viruses such as Hepatitis B (HB), non-A, non-B Hepatitis (NANBH), Human T Lymphotrophic Retrovirus Type 3 (HTLV), Human Immunodeficiency Virus (HIV), and Lymphadenopathy Associated Virus (LAV). At present, the method of choice for inactivating these viruses in blood and blood fractions is treatment with a solvent such as tri-n-butyl phosphate and a detergent such as polysorbate 80 (Tween 80) or sodium cholate. Much of the early work in this area was done by the group of Bernard Horowitz and Alfred Prince at the New York Blood Center and as of February 1991, over 1.7 million doses of solvent and detergent treated coagulation factor concentrates had been infused.
In addition to tri-n-butyl phosphate, other phosphate esters, ether and halohydrocarbons have been described as useful solvents. In addition to polysorbate or sodium cholate detergents, other nonionic surfactants, particularly ethoxylated octylphenols and nonylphenols, as well as sulfobetaines, phosphatidyl cholines and octyl .beta.-D-glucopyranoside have been mentioned as vital inactivating agents. For example, U.S. Pat. No. 4,540,573 describes the use of a number of organic solvent and detergent pairs to reduce the infectivity of hepatitis and other viruses.
In all of the foregoing treatments, exogenous agents are added to the biological fluid. In most cases, these exogenous agents must be removed from the biological fluid before it can be administered to a human. European application 239,859 describes a method that is currently employed to remove lipid soluble process chemicals from biological fluids. It comprises bringing the fluid into contact with a naturally occurring oil, agitating the resultant mixture, separating the phases by sedimentation or centrifugation, decanting the upper lipid phase, and utilizing the residual biological fluid. Aside from the mechanical complexity of this process, it appears applicable only to the removal of lipid soluble process chemicals (such as tri-n-butyl phosphate). Indeed the application indicates that a common non-ionic surfactant (polysorbate 80) is poorly extracted.
Gel filtration has also been proposed for removing detergents and solvents from blood fractions based on molecular weight differences. Horowitz et al. [Tranfusion 25, p. 516-522 (1985)] have described the removal of tri-n-butyl phosphate from anti-hemophilic factor concentrates by chromatography on Sephadex G-25; however, gel chromatography is not a practical method for removing solvent and detergent from whole blood. Moreover, it was ineffective for the removal of polysorbate 80 from a blood component, although effective for removing sodium cholate. Horowitz et al. [Blood, 79, p. 826-831 (1992)] have also suggested the removal of tri-n-butyl phosphate and Triton.sup..cndot. X-100 (polyethoxylated octylphenol) from fresh frozen plasma by extraction with soybean oil, centrifugation, and then preparative chromatography on C-18 reverse phase.
None of the methods presently in use or proposed is particularly attractive for the routine processing of blood and blood fractions. There is thus a need for a simple and effective method for removing small exogenous molecules, both hydrophobic and polar, from blood and other biological fluids.
It is therefore an object of the present invention to provide a method for removing small exogenous molecules from a biological fluid quickly and efficiently.
It is another object of the invention to provide a method that can remove exogenous molecules without impairing the function of the biological fluid.
It is a further object to provide a method for removing exogenous molecules that can remove both hydrophobic and amphiphilic molecules.
It is a more particular object of the present invention to provide a method for removing vital inactivating agents from blood or blood fractions quickly and efficiently in a clinical setting.
It is a further object of the invention to provide a porous support suitable for removing small exogenous molecules without impairing the function of the biological fluid.
These and other objects, features and advantages are provided by the instant invention summarized below.